Do you know how many Big 12 teams played Gonzaga? 5. Do you know how many Big 12 teams beat Gonzaga? 0. Do you know how many Big 12 teams came within 15 points of beating Gonzaga? 2. And Gonzaga didn't play TCU, Texas, or Texas Tech. My point is that the 8th place team in the Big Ten did what no one from the Big 12, not even the top dogs, could do. And they did it in Spokane, no less.
Also, look at West Virginia. They lost to Kansas State by 1, lost on a buzzer beater at ISU, lost at OK State by 14, and lost to Kansas by 5. In between those games, they lost to Purdue by 27.
Conclusion: Outside of the top 4, the teams in the Big Ten are mediocre by Big Ten standards, which makes them better than the good teams of every other conference.